The present invention relates to routing templates and more particularly to such templates adapted for routing stair stringers.
A wide variety of templates has been developed for routing wooden or other stair stringers. Typically, such a template includes a body defining generally perpendicularly oriented tread and riser slots and a clamping structure for securing the template to the stringer. After the template is properly positioned, a router is run along and within the tread and/or riser slots to form the recesses in the stringer for receiving the boards which form the treads and risers. The recesses routed into the stringers enhance the structural integrity of the staircase and provide an aesthetically jointed construction. Known templates are however either unadjustable or, if adjustable, relatively complicated and cumbersome.
One known adjustable stair step routing template is disclosed in U.S. Pat. No. 1,552,881, issued Sept. 8, 1925, to Rose, and entitled SPINDLE MOLDING MACHINE FOR WOOD. The template includes a pair of linear guides adjustably secured to opposite sides of the template body to register with scales indicating the selected tread depth and riser height. This template, however, has several drawbacks. The linear guides which extend from both sides of the template prohibit the direct use of a router in conjunction with the template. Consequently, a relatively complicated follower assembly is required to rout the stringer. Second, adjustment of the Rose template is relatively difficult because the linear guides can be adjusted only by loosening both wing nuts, adjusting the guides, and resecuring the wing nuts. An adjustment to the tread depth affects the riser height and vice-versa, further complicating adjustment. Finally, the linear guide can be knocked out of adjustment.
Other templates have been developed which are not adjustable and therefore provide a fixed tread depth and riser height. Although these templates are useful on a standard width board for a standard size stair, they are unsuitable for general purpose use wherein the board width and stair measurements vary.